This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A147746 #18 Jul 19 2019 11:44:26
%S A147746 1,0,1,0,1,1,0,2,2,1,0,5,5,3,1,0,13,14,9,4,1,0,34,40,28,14,5,1,0,89,
%T A147746 114,87,48,20,6,1,0,233,323,267,161,75,27,7,1,0,610,910,809,528,270,
%U A147746 110,35,8,1
%N A147746 Riordan array (1, x(1-2x)/(1-3x+x^2)).
%C A147746 Triangle [0,1,1,1,0,0,0,....] DELTA [1,0,0,0,...] with Deléham DELTA as in A084938.
%C A147746 Note that 1/(1-x/(1-x/(1-x))) = (1-2x)/(1-3x+x^2). Row sums are A124302.
%C A147746 A147746*A007318 = A147747.
%F A147746 Sum_{k=0..n} T(n,k)*2^k = A147748(n). - _Philippe Deléham_, Oct 30 2011
%F A147746 Sum_{k=0..n} T(n,k)*(-1)^(n-k) = A215936(n). - _Philippe Deléham_, Aug 30 2012
%F A147746 G.f.: (1 - 3*x + x^2)/(1 - 3*x + x^2 - x*y + 2*x^2*y). - _R. J. Mathar_, Aug 11 2015
%e A147746 Triangle begins
%e A147746 1;
%e A147746 0, 1;
%e A147746 0, 1, 1;
%e A147746 0, 2, 2, 1;
%e A147746 0, 5, 5, 3, 1;
%e A147746 0, 13, 14, 9, 4, 1;
%e A147746 0, 34, 40, 28, 14, 5, 1;
%e A147746 0, 89, 114, 87, 48, 20, 6, 1;
%e A147746 ...
%t A147746 (* The function RiordanArray is defined in A256893. *)
%t A147746 RiordanArray[1&, # (1-2#)/(1-3#+#^2)&, 10] // Flatten (* _Jean-François Alcover_, Jul 19 2019 *)
%K A147746 easy,nonn,tabl
%O A147746 0,8
%A A147746 _Paul Barry_, Nov 11 2008